1. Field of the Invention
The present invention relates to an electronic component. In more detail, the present invention relates to an electronic component with a shield case for housing surface mounted components mounted on a substrate.
2. Description of the Related Art
Electronic components comprises an electronic component 60 with a shield case 65 for housing surface mounted components 64 as shown in FIG. 8.
The electronic component with such shield case has been manufactured by the manufacturing method as described below:
(1) Through-holes 62 are formed on a sheet substrate (a mother substrate) 61 provided with a plurality of substrates 51 for mounting the components, and an electrode 63 for attaching the shield case is formed on an inner circumference face (side face) of each through hole 62 as shown in FIG. 9.
(2) In the next step, the surface mounted component 64 is mounted on a sheet substrate (the mother substrate) 61, and the surface mounted component 64 is soldered to land electrodes (not shown) of the sheet substrate 61.
(3) Subsequently, a solder paste 67 is filled in the through holes 62.
(4) Then, engaging pins 66 of a plurality of the shield cases 65 are inserted into the through holes 62 filled with the solder paste 67.
(5) Then, a plurality of the shield cases 65 are soldered to the sheet substrate 61 by melting the solder in the solder paste 67. The shield cases 65 are connected and fixed to the sheet substrate 61 as shown in FIG. 8 by soldering the engaging pins 66 to the fixing electrodes (shield case attachment electrodes: FIG. 9) 63 in the through holes 62.
(6) Finally, an individual electronic component 60 as shown in FIG. 8 is obtained by cutting the sheet substrate 61 along the lines (cutting lines) Axe2x80x94A using a dicing machine.
The through hole 62 formed on the sheet substrate (mother substrate) 61 has a larger diameter than the width of the engaging pin 66 so that the engaging pin 66 can be easily inserted. Consequently, the shield case 65 is engaged with the through hole with a little gap (play) when the shield case 65 is attached to the sheet substrate 61 by inserting the engaging pin 66 into the through hole 62 in the step for preparing the sheet substrate 61, thereby causing an improper alignment in the subsequent manufacturing step to adversely affect the configurational and dimensional accuracy, and shield characteristics.
Otherwise, the solder that serves for fixing the engaging pin 66 to a fixing electrode 63 of the through hole 62 re-melts in the reflow soldering step for mounting on the printed circuit board, and in the step for manufacturing the individual electronic component 60 (FIG. 8) obtained by cutting the sheet substrate 61 after soldering a plurality of the shield cases 65 on the sheet substrate 61, arising a problem of positional shift of the shield cases 65 or falling of the shield cases 65 out of the substrate to make the component to go out of use.
Accordingly, the object of the present invention for solving-the problems as hitherto described is to provide an electronic component having high positional accuracy in attaching the shield case to the substrate and high shield performance as well as high mounting reliability.
The present invention for attaining the foregoing objects provides an electronic component with a shield case for housing surface mounted components on a substrate comprising: a substrate provided with engaging recesses for attaching a shield case at plural sites on the side face of the substrate; a surface mounted component mounted on the substrate; and a shield case having a main body covering the surface for mounting the surface mounted component of the substrate, and a plurality of engaging pins to be inserted into the engaging recesses of the substrate, the shield case being so configured as to be bent when predetermined engaging pins are engage with the substrate by inserting the engaging pins into the corresponding engaging recesses of the substrate, wherein the plural engaging pins on the shield case hold the substrate with enhanced elastic force.
The substrate can be securely held with a plurality of the engaging pins inserted into the engaging recess of the substrate by providing the engaging recess on the side face of the substrate and a plurality of the engaging pins on the shield case, the shield case being so configured as to be bent when given engaging pins engage with the substrate by inserting the engaging pins into designated engaging recesses of the substrate, wherein the plural engaging pins on the shield case hold the substrate with enhanced elastic force. Consequently, the shield case has a high positional accuracy for attaching to the substrate and an excellent shielding performance, thereby enabling an electronic component with a shield case with high reliability for mounting.
According to the present invention the configuration of the shield case that allows the shield case to be bent when the engaging pin is inserted into the engaging recess of the substrate as used in the electronic component having the shield case. The configuration of the shield case includes a wide range of concepts such as a configuration for allowing the engaging pin of the shield case to be deflected, a configuration for allowing the main body of the case to be deflected, or a configuration for allowing both of the engaging pin and the main body of the case to be deflected.
In the electronic component with the shield case according to the present invention, the main body of the case and the engaging pins can be made of the unitary member. Otherwise, separate main body of the case and engaging pins can be combined and integrated.
Preferably, a projection or a bending portion is provided on the engaging pin to be engaged with the engaging recess of the substrate.
Providing a projection or a bending portion on the engaging pin of the shield case allows the shield case to be securely connected to the substrate. Consequently, fixing strength of the shield case to the engaging recess of the substrate is improved, thereby positional accuracy of an electronic component for attaching the shield case to the substrate is improved. Further, shielding performance and reliability for mounting is improved.
Preferably, the engaging pins are protruded from the lower surface of the substrate, the shield case being fixed to the substrate by bending the protruding portions of the engaging pins from the lower surface of the substrate.
When the engaging pin is protruded from the lower face side of the substrate, and when the pin protruding from the lower face side of the substrate is bent, the shield case can be securely fixed to the substrate in the manufacturing step, enabling occurrence of positional shift of the shield case to be securely prevented.
In the electronic component with the shield case according to the present invention, preferably, a step portion is provided on the inner circumference of the engaging recess of the substrate, the step portion is engaged with the engaging pin of the shield case.
Forming a step portion for engaging with the engaging pin of the shield case allows reliability for engaging the engaging pin with the engaging recess to be improved. Accordingly reliability of positional accuracy for attaching the shield case to the substrate and shielding performance is further improved.
Preferably, a land electrode for electrical connection to the shield case is provided at the periphery of the engaging recess for mounting the surface mounted component on the substrate, the land electrode being connected to a part of the shield case with a solder.
Providing a land electrode for electrical connection to the shield case at the periphery of the engaging recess to connect a part of the shield case to the land electrode with a solder allows reliability of electrical connection to be improved.
Preferably, a solder plating or a tin plating for improving solderability is applied on the portion of the shield case to be soldered to the land electrode.
Using a shield case subjected to solder plating or tin plating on the portion of the shield case to be soldered to the land electrode allows solderability of the shield case to be improved, thereby further improving reliability for electrical connection.